TAURINE I N MARINE INVERTEBRATES
217
though cysteine sulphinic acid is known t o be present and that the
latter can be formed from S35 methionine (Bergeret and Chatagner,
1954; Peck and Awapara, 1966). This is also true of rat heart and it
must be concluded that another pathway is present in these tissues
(see below).
Fromageot et al. (1948) showed that under anaerobic conditions,
cysteine sulphinic acid in the presence of rabbit liver extract gave rise
to alanine and sulphite by desulphination. This work was followed by
further experiments by Chatagner and Bergeret (1951, 1955), Bergeret and Chatagner (1952,1954,1956) and Bergeret et al. (1952) in which,
by increasing the amount of cysteine sulphinic acid in the above experiment followed by paper chromatographic separation, they found an
additional and new neutral sulphur amino compound which they
suggested was formed by decarboxylation of the cystcine sulphinic
acid and which they named hypotaurine.
COOH
CH.NH,I
CH3.S0,H
CH,.NH,
t co,
I
I
CH,.SO,H
CYSTEINE SULPHINIC ACID
HYPOTAURINE
This they confirmed manometrically and also showed that hypotaurine was produced in vivo in rats following injection of liver extract.
of control rats previously injected with L-cysteine sulphinic acid.
Furthermore, they found it was present in small amounts in the liver
of normal animals. Bergeret and Chatagner (1952) and Bergeret et al.,
(1952) showed that both the formation of alanine and SO, and of hypotaurine from L-cysteine sulphinic acid was enzymatic. These observations are clearly related t o those of Awapara et al. (1950) when the latter
found that alanine as well as taurine is formed in the liver after injection
of cysteine. When Awapara (1953) and Awapara and Wingo (1953)
repeated the earlier experiments they too found hypotaurine (2aminoethanesulphinic acid) in the liver of rats. Awapara (1 953)
suggests that the following two-step reaction takes place in the liver:
Oxidation of cysteine to cysteine sulphinic acid and decarboxylation
of the latter to hypotaurine. I n addition Awapara and Wingo (1953)
suggest that cysteic acid, which Medes and Floyd ( 1942) and Blaschko
(1 942) had found t o give taurine on decarboxylation, was not in fact
the normal precursor, but that the above was the preferred pathway
(Fig. 1). Furthermore, the results of the latter workers could be ex-
217
though cysteine sulphinic acid is known t o be present and that the
latter can be formed from S35 methionine (Bergeret and Chatagner,
1954; Peck and Awapara, 1966). This is also true of rat heart and it
must be concluded that another pathway is present in these tissues
(see below).
Fromageot et al. (1948) showed that under anaerobic conditions,
cysteine sulphinic acid in the presence of rabbit liver extract gave rise
to alanine and sulphite by desulphination. This work was followed by
further experiments by Chatagner and Bergeret (1951, 1955), Bergeret and Chatagner (1952,1954,1956) and Bergeret et al. (1952) in which,
by increasing the amount of cysteine sulphinic acid in the above experiment followed by paper chromatographic separation, they found an
additional and new neutral sulphur amino compound which they
suggested was formed by decarboxylation of the cystcine sulphinic
acid and which they named hypotaurine.
COOH
CH.NH,I
CH3.S0,H
CH,.NH,
t co,
I
I
CH,.SO,H
CYSTEINE SULPHINIC ACID
HYPOTAURINE
This they confirmed manometrically and also showed that hypotaurine was produced in vivo in rats following injection of liver extract.
of control rats previously injected with L-cysteine sulphinic acid.
Furthermore, they found it was present in small amounts in the liver
of normal animals. Bergeret and Chatagner (1952) and Bergeret et al.,
(1952) showed that both the formation of alanine and SO, and of hypotaurine from L-cysteine sulphinic acid was enzymatic. These observations are clearly related t o those of Awapara et al. (1950) when the latter
found that alanine as well as taurine is formed in the liver after injection
of cysteine. When Awapara (1953) and Awapara and Wingo (1953)
repeated the earlier experiments they too found hypotaurine (2aminoethanesulphinic acid) in the liver of rats. Awapara (1 953)
suggests that the following two-step reaction takes place in the liver:
Oxidation of cysteine to cysteine sulphinic acid and decarboxylation
of the latter to hypotaurine. I n addition Awapara and Wingo (1953)
suggest that cysteic acid, which Medes and Floyd ( 1942) and Blaschko
(1 942) had found t o give taurine on decarboxylation, was not in fact
the normal precursor, but that the above was the preferred pathway
(Fig. 1). Furthermore, the results of the latter workers could be ex-